Stacked chip arrangements can provide significant advantage in packing density and performance. The closest packing density is achieved where the chips are glued directly to each other. However, chip reliability is much more important in this arrangement since a short anyplace on the stack can render the entire stack defective. Schemes to disconnect shorted chips and connect spare good chips have been proposed. One scheme, described in commonly assigned U.S. Pat. No. 5,414,637 to Bertin et al, requires an additional thin film metal layer, an insulation layer, and a via there between on the side face of the stack, adding significantly to process complexity and cost. Another, described in commonly assigned U.S. Pat. No. 5,661,330, to Aimi, et al., provides fuses for each pad of the stack. These schemes both provide that the stack pad layout changes depending on which chips of the stack are being used, raising the cost of making connection to the stack. These schemes have also provided several major manufacturing steps after repair is complete, introducing the possibility of defects that could require further repair.
Thus, a better solution is needed that provides the ability to replace shorted chips using simple steps after all other manufacturing steps are complete.